Citrix Systems 5.6 manual Configuring a dedicated storage NIC, Controlling Quality of Service QoS

Configuring a dedicated storage NIC

XenServer allows use of either XenCenter or the xe CLI to configure and dedicate a NIC to specific functions, such as storage traffic.

Assigning a NIC to a specific function will prevent the use of the NIC for other functions such as host management, but requires that the appropriate network configuration be in place in order to ensure the NIC is used for the desired traffic. For example, to dedicate a NIC to storage traffic the NIC, storage target, switch, and/or VLAN must be configured such that the target is only accessible over the assigned NIC. This allows use of standard IP routing to control how traffic is routed between multiple NICs within a XenServer.

Note:

Before dedicating a network interface as a storage interface for use with iSCSI or NFS SRs, ensure that the dedicated interface uses a separate IP subnet which is not routable from the main management interface. If this is not enforced, then storage traffic may be directed over the main management interface after a host reboot, due to the order in which network interfaces are initialized.

To assign NIC functions using the xe CLI

1.Ensure that the PIF is on a separate subnet, or routing is configured to suit your network topology in order to force the desired traffic over the selected PIF.

2.Setup an IP configuration for the PIF, adding appropriate values for the mode parameter and if using static IP addressing the IP, netmask, gateway, and DNS parameters:

xe pif-reconfigure-ip mode=<DHCP Static> uuid=<pif-uuid>

3.Set the PIF's disallow-unplug parameter to true:

xe pif-param-set disallow-unplug=true uuid=<pif-uuid>

xe pif-param-set other-config:management_purpose="Storage" uuid=<pif-uuid>

If you want to use a storage interface that can be routed from the management interface also (bearing in mind that this configuration is not recommended), then you have two options:

•After a host reboot, ensure that the storage interface is correctly configured, and use the xe pbd-unplugand xe pbd-plugcommands to reinitialize the storage connections on the host. This will restart the storage connection and route it over the correct interface.

•Alternatively, you can use xe pif-forgetto remove the interface from the XenServer database, and manually configure it in the control domain. This is an advanced option and requires you to be familiar with how to manually configure Linux networking.

Controlling Quality of Service (QoS)

Citrix XenServer allows an optional Quality of Service (QoS) value to be set on VM virtual network interfaces (VIFs) using the CLI. The supported QoS algorithm type is rate limiting, specified as a maximum transfer rate for the VIF in Kb per second.

For example, to limit a VIF to a maximum transfer rate of 100kb/s, use the vif-param-setcommand:

xe vif-param-set uuid=<vif_uuid> qos_algorithm_type=ratelimit xe vif-param-set uuid=<vif_uuid> qos_algorithm_params:kbps=100

Changing networking configuration options

This section discusses how to change the networking configuration of a XenServer host. This includes:

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